England's striker Jermain Defoe (R) holds Bradley Lowery, a five-year-old suffering from terminal cancer, mascot for the match, ahead of the World Cup 2018 qualification football match between England and Lithuania at Wembley: Getty

Bradley Lowery, the terminally ill young football fan who has struck up a friendship with England and Sunderland striker Jermain Defoe, has been accepted onto a new clinical trial offering potentially lifesaving treatment.

The five-year-old who suffers from neuroblastoma – a rare form of cancer that affects his nerves - will trial CAR-T therapy.

The youngster from Blackhall, County Durham, rose to public attention when he walked out with Defoe as a mascot for England’s World Cup qualifier against Lithuania.

The pair have formed an unlikely friendship after the 34-year-old forward visited him in hospital.

A post on Bradley’s Facebook page said that he had had a “tough week” and was still “not too grand”.

But it added that he was "out of hospital now and spending some time with his grandparents".

Bradley's parents were to travel to to Great Ormond Street hospital in London to discuss his place on the CART Therapy trial funded by Cancer Research UK.

Testing of the has “shown promising results in the past”, his Facebook post said.

Neuroblastoma is the most common paediatric cancer outside of the brain and is a significant cause of death among children.

The cell treatment has shown some success in trials of people with leukaemia and lymphoma where it has induced remissions.

“Bradley has scans next week to see if his current treatment is working, therefore we cannot decide what's next until we get the scan results," the Facebook post said. “We are hoping and praying for good news, please keep him in your prayers."